grinding a radius on an end mill

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H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Jun 26, 2016
I need to obtain an end mill that cuts a 1/8" radius (inner radius, like a fillet, not a round over if that makes sense). I have not been able to find any reasonably prices end mills so I was wondering it that would be a straight forward thing to modify an standard end mill. I have just obtained a single lip cutter grinder (British clone of a Deckel SO). Would that do it? Has anyone done this before? I was even thinking of trying it by hand on a 2 flute end mill using a radius gauge, but that seems a bit crude. Any suggestions?


Scott in MOntreal

Bob Korves

H-M Supporter - Sustaining Member
H-M Platinum Supporter ($50)
Jul 2, 2014
Like BillH50 said. The end mill can be radiused offhand on a grinder, and then clearance is carefully added behind the cutting edges to keep them from rubbing. I have a pile of ball end mills that someone has done that to, probably after a corner was chipped off the square cutting end mill. If the end mill is only slightly chipped off at the corner, a smaller radius can be made in the same way, which will leave a nicely radiused corner on the work. Don't throw a sharp end mill away just because it has lost a chunk off the corner!
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